The Girl on the Train
Synopsis

After her divorce, a woman named Rachel Watson (Emily Blunt) experiences severe depression. While traveling daily by train to the city to get to her job, Rachel finds some comfort when she sees what she believes to be the "perfect" couple, Scott (Luke Evans) and Megan (Haley Bennett), and creates an imaginary fantasy life for them.

However, when she later witnesses Megan kissing another man, it angers her, even though she doesn't actually know the people involved. The next day, when she wakes up with no memory of the night before and finds out that Megan has gone missing, Rachel finds she can't help but get involved in their drama/murder mystery.